I have an Isolation transformer 3600 connected to shore power 30 amp 110volt, with a breaker before the transformer. Works fine and provides 110 to boat except at one marina. When connected at this marina, green light (power) goes on, but neither yellow light is on and there is no current at the output. no red light or heat issue, as the unit has just come on. When I bypass the 3600, I get 120 volts at the outlets and the charger and hot water work. I also tried the 50 amp socket with a 50 to 30 amp plug, but same issue. Any ideas on what is causing the failure at one location that seems to have power for everyone else?